Everyone knows that it is a good thing to turn off your faucet when not in use to save water, but how many know that this simple practice also saves energy and reduces global warming – by a lot! Ali Bakhshi, a PhD student in Civil and Infrastructure Engineering, is researching the “embodied energy” of water used by facilities. Ali uses the carbon footprint metric to estimate a system’s sustainable performance over its expected life cycle. The metric, represented in terms of tons per year of carbon dioxide, provides a valuable energy and environmental baseline for commercial and residential buildings. Imagine carrying one gallon of water for several miles and up and incline of 200 feet of so. That gives you an idea of the energy required to pump one gallon of water. Now add on the energy required to treat the water, collect the wastewater and treat the wastewater and you have an idea of the embodied energy associated with water use.
As one can imagine, the water delivery to the building and removal of wastewater from the building creates a sizable carbon footprint. The embodied energy associated with water and wastewater treatment and delivery depends on topographical characteristics of the local water supply and treatment system, and the wastewater collection and treatment system. The questions Ali is attempting to answer are: What is the impact of demand side sustainable water practices on the embodied energy as represented by a comprehensive carbon footprint? What are the major energy consuming elements attributed to the system? What is a viable and visually identifiable tool to estimate the carbon footprint attributed to those Greenhouse Gas (GHG) producing elements? What is the embodied energy and emission associated with water use delivered to a building?
Simple carbon footprint calculators are available to convert energy consumption of industrial processes and building operations to tons of carbon such as the EPA Greenhouse Gas Equivalencies Calculator http://www.epa.gov/cleanenergy/energy-resources/calculator.html. Unfortunately, these tools are not comprehensive because they lack estimates for the embodied energy of water distribution and treatment. Ali plans to utilize a Geographic Information System (GIS) model for embodied energy calculations. Factors that affect the carbon footprint will be investigated and the use of the GIS model as a sustainability planning framework will evaluated.
Benefits to be derived from a standardized GHG approach include:
- Improved environmental and economic information for the developers, water and wastewater processing and municipal planners;
- Improved energy use reporting and conservation planning;
- Establishment of a benchmark for GHG emissions attributed to the water and wastewater industry for particular geographic region;
- Ability to quantify relative impacts of building design options using carbon emission equivalents.
The estimation of energy consumption and subsequent carbon footprint calculation relies not only on the quantity of water distributed but also the geography of the distribution and collection network. Critical variables that contribute significantly to the energy consumption will be determined based on a sensitivity analysis. Ali’s research answers critical questions related to the impact of demand side sustainable water practices on the comprehensive carbon footprint.